Gill C O, Bryant J, Badoni M
Agriculture Agri-Food Canada Research Centre, Lacombe, Alberta.
Int J Food Microbiol. 2001 Feb 15;63(3):243-56. doi: 10.1016/s0168-1605(00)00430-x.
Ten 12-kg lots of manufacturing beef from a single packing plant were obtained from a hamburger patty manufacturing plant. Each lot was divided into two, 6-kg portions, one of which was not treated while the other was treated with water of 85 degrees C. A portion from one lot was treated for 15 s. A portion from each of three lots was treated for 30 s, three portions were treated for 45 s, and three were treated for 60 s. Twenty-five pieces of meat from each portion were swabbed over areas of 100 cm2. Subsequently, each portion was first coarsely ground then finely ground, with twenty-five 100-g samples being taken from each portion at each stage of grinding. Each swab and sample of ground meat was separately processed for the enumeration of total aerobic counts, coliforms and Escherichia coli at levels of detection of 1 cfu/cm2, 1 cfu/100 cm2 and 1 cfu/100 cm2, respectively, for swab samples; and at a level of detection of 1 cfu/g for all three types of bacteria in samples of ground beef. A 250-kg batch of manufacturing beef was treated with water of 85 degrees C for 60 s. The product was processed through commercial equipment for manufacturing frozen hamburger patties. The flavour of patties prepared from the pasteurized product was compared with the flavour of patties prepared during normal commercial operation of the equipment. The weight of the manufacturing beef was not affected by the treatments. Similar total numbers of coliforms or E. coli were recovered per 2500 cm2 from the 25 swab samples or per 25 g from the 25 ground beef samples from each untreated portion. As the ratio of the surface area in cm2 to the weight in g would likely be < or = 1, the similar numbers indicated that swab sampling was inefficient for recovering coliforms and E. coli from the meat. However, coliforms and E. coli were recovered more frequently from swab than from ground beef samples from treated portions. Thus, some swabs from all three portions of beef treated for 30 s yielded coliforms and E. coli, but samples from portions treated for 45 or 60 s yielded few coliforms and no E. coli. The numbers recovered from the treated and untreated portions indicated that treatments for 45 or 60 s reduced both coliform and E. coli numbers by two orders of magnitude. The flavours of cooked patties prepared from the meat pasteurized with water of 85 degrees C for 60 s were not distinguished from the normal commercial product. The data indicate that pasteurizing manufacturing beef with water of 85 degrees C for 45 s could be a practicable treatment for enhancing the microbiological safety of frozen hamburger patties.
从一家汉堡肉饼生产厂获取了来自单个包装厂的10批12千克的生产用牛肉。每批牛肉被分成两份，每份6千克，其中一份不做处理，另一份用85摄氏度的水进行处理。从一批牛肉中取一份处理15秒。从三批牛肉中各取一份处理30秒，三份处理45秒，三份处理60秒。对每份牛肉的25片在100平方厘米的区域进行擦拭取样。随后，每份牛肉先粗磨再细磨，在每个研磨阶段从每份牛肉中取25个100克的样本。每个擦拭样本和磨碎牛肉样本分别进行处理，以分别在检测限为1 cfu/平方厘米、1 cfu/100平方厘米和1 cfu/100平方厘米的水平下对需氧菌总数、大肠菌群和大肠杆菌进行计数；对于磨碎牛肉样本，三种细菌的检测限均为1 cfu/克。一批250千克的生产用牛肉用85摄氏度的水处理60秒。该产品通过商业设备加工成冷冻汉堡肉饼。将用巴氏杀菌产品制作的肉饼风味与设备正常商业运行期间制作的肉饼风味进行比较。处理并未影响生产用牛肉的重量。从未经处理的每份牛肉的25个擦拭样本（每2500平方厘米）或25个磨碎牛肉样本（每25克）中回收的大肠菌群或大肠杆菌总数相似。由于平方厘米的表面积与克重量的比值可能≤1，相似的数量表明擦拭取样从肉中回收大肠菌群和大肠杆菌的效率不高。然而，与处理过的牛肉样本相比，从擦拭样本中更频繁地回收大肠菌群和大肠杆菌。因此，处理30秒的所有三份牛肉中的一些擦拭样本检出了大肠菌群和大肠杆菌，但处理45秒或60秒的样本中大肠菌群检出较少且未检出大肠杆菌。从处理和未处理部分回收的数量表明，处理45秒或60秒可使大肠菌群和大肠杆菌数量减少两个数量级。用85摄氏度的水巴氏杀菌60秒的肉制作的熟肉饼风味与正常商业产品无异。数据表明，用85摄氏度的水对生产用牛肉进行45秒的巴氏杀菌可能是提高冷冻汉堡肉饼微生物安全性的一种可行处理方法。
